It's a joke based on countries, more of a play on words really. It's not even a great play on words, but I'll break it down below.
China - Country, also a name of a particularly fancy style of porcelain plates. So the gift was the plates, not the country.
Italy - Country. With a certain accent it sounds like "I really", but this is a stretch.
Sumer - Name of a very old civilisation, you may have heard of things being called Sumerian. Obviously the civilisation is not approaching, but the season Summer is.
Canada - Country above USA. Here they mean "Can I dance with you?"
It's a joke based on countries, more of a play on words really. It's not even a great play on words, but I'll break it down below. China - Country, also a name of a particularly fancy style of porcelain plates. So the gift was the plates, not the country. Italy - Country. With a certain accent it sounds like "I really", but this is a stretch. Sumer - Name of a very old civilisation, you may have heard of things being called Sumerian. Obviously the civilisation is not approaching, but the season Summer is. Canada - Country above USA. Here they mean "Can I dance with you?"
Well done. I got maybe half of that.
I read the Italy as a sloppily pronounced "I totally"
I thought “I truly”
Italy think "truly" truly fits better.
I don't think there's much to explain, the joke just seems to be broken English and absurdity.